Weekly Weather: Winter Storm edition

Good morning and welcome to my weekly weather report on the immediate past, present and future of weather in the Bayou City.

PAST

As I’ve written before, Houston had a fairly normal weather year in 2013, but there were some significant moments, notably, the mark of 107 degrees on June 29, the highest temperature ever recorded in June.

These moments are encapsulated in the graphic below, by Jay Carr, which shows the year’s weather in a glance.

What I want to call your attention to is Oct. 5. After that date you’ll note that temperatures above normal are far less frequent than below normal temperatures, especially the overnight lows. We have had significantly cooler-than-normal weather since then, and this is a trend that will definitely continue this week.

It’s the calm before the storm this morning, with highs in the upper 50s to low 60s across the metro area.

But a cold front, with much drier and colder air behind it, is moving quickly through Texas toward the city of Houston. It should arrive in the city by about 10 a.m., or so, and push off the coast by around noon.

Although it will be cold on Monday night, the real fireworks will come on Tuesday, when an upper-level disturbance moves into southeast Texas and brings a good chance of precipitation to the area. The key questions are how much, and how much of the precipitation will make it to the ground in a frozen state.

In their Winter Storm Watch, forecasters from the National Weather Service say the system should bring a mix of freezing rain and sleet to areas just north of Houston on Tuesday morning, with 1 to 2 inches of snow possible. This precipitation will move into Houston later, by mid-morning or noon.

What will happen in the city?

As we discussed last week, for snow to fall the temperature must be freezing throughout the atmosphere above the surface. At this point, tomorrow, it appears there will be an area of warmer air above the surface, meaning that at least initially on Tuesday precipitation that falls in Houston and along the coast will either fall as rain, and freeze on contact, or fall as sleet. In either case it could make travel on roadways hazardous throughout the metro area, especially in areas where accumulations are greatest, as surface temperatures should only briefly reach the above-freezing level on Tuesday.

Will it snow? At some point on Tuesday afternoon and evening the entire column of the atmosphere above at least parts of the city should cool to below-freezing levels, allowing for snow to mix in. The question is, will the precipitation stop before this happens? right now the forecast models end the wintry precipitation by late Tuesday afternoon or early evening.

How cold will it get on Wednesday morning? Quite cold, forecasts the GFS model. (Weather Bell)

Tuesday night will be very cold, with temperatures falling into the 20s by Wednesday morning.

After a cold and sunny day Wednesday, with highs near 40 degrees, Houston will finally see a significant warm-up, with temperatures climbing back into the 70s by Friday.

FUTURE

Is this the last bitter arctic cold front of the season?

Unfortunately I can’t make that promise. For example, the 16-day GFS model forecasts another outbreak of very cold air around Feb. 5, with another swing into the 20s possible. While this is a ways out, and confidence in model forecasts that far down the road is low, it would be consistent with the pattern we’ve seen so far this winter.

Finally, if you want several daily updates on weather, please “like” my SciGuy Facebook page. It’s the best place for multiple daily updates on our weather, delivered right to your news feed.

FINE PRINT

As always, thank you to the fine professionals at the National Weather Service for the information and data that make this weekly blog entry possible. Also, bear in mind there’s always uncertainty in weather forecasting, particularly the timing and intensity of precipitation.

It seems likely that schools in Walker and Montgomery County will close Tuesday. Can we expect ice and snow to still be on the ground come Wednesday morning in places like Conroe and Huntsville? I’m wondering if I need to prepare for a delay Wednesday morning. Thanks!

You’re still thinking that we’ll see overnight lows in the 20’s Tues/Wed? The forecast on Weather Underground is only talking about a low of 31 which would have most of the precip stay liquid or melt as it falls on Tuesday afternoon and evening. Still worried about bridges and ramps, but it (hopefully) won’t be a severe as it might be.

Yes, I have been doing the same thing. I bring the aloe vera in the house, because they have a lot of water which can freeze and rupture the vessels inside the leaves. Then my cats rip at it. My jasmine weighs a ton and a drag that into my unheated garage, and so far it hasn’t frozen the past couple of cold nights.

Moving potted plants, and covering the rest, is a nice form of excercise. I am getting pretty good at it this winter.
I only wish we were getting some serious rain during this period.
Good review, by the way.
Stay warm!

So, if I were planning on heading from inside the loop up to IAH at around 5:30 in the morning tomorrow, it looks like I should be OK? I know timing is difficult to nail down, but trying to decide if I need to change my flight.

Eric – Do you have any feel for when HISD/Harris Co Emergency Mgmt will begin to make decisions about closures, etc? I am trying to pull together the contingency plans for my office and want to base our decision on how the various city/county departments are proceeding.

What is the criteria for the Watch to be upgraded to a Warning? Also, seems like maybe this won’t be as significant of a system as previously thought? If so, that’s a bummer, but not surprised after the last time we thought we would get a lot of snow and nothing happened.